Which one of the following is incorrect?

Options

A. fertilization follows capacitation
B. cleavage of fertilized ovum results in blastula
C. fusiion of sperm and ovum occurs in fallopian tube
D. cleavage leads to increase in the mass of protoplasm

Answer

**Step-by-Step Solution:**

1. **Understanding Capacitation**: The first statement mentions that fertilization follows capacitation. Capacitation is a process that sperm undergo to gain the ability to fertilize an egg. This statement is correct.

2. **Cleavage and Blastula Formation**: The second statement discusses the cleavage of a fertilized ovum resulting in a blastula. After fertilization, the zygote undergoes cleavage (mitotic divisions) to form a morula, which then develops into a blastula. This statement is also correct.

3. **Fusion of Sperm and Ovum**: The third statement states that the fusion of sperm and ovum occurs in the fallopian tube. This is true as fertilization typically occurs in the fallopian tube, specifically at the isthmic junction. Therefore, this statement is correct.

4. **Cleavage and Protoplasm Mass**: The fourth statement claims that cleavage leads to an increase in the mass of protoplasm. This is incorrect because during cleavage, the zygote divides into multiple cells (blastomeres) without an increase in the overall mass of protoplasm. The total volume remains the same; only the number of cells increases.

5. **Conclusion**: The incorrect statement among the options provided is the fourth one, which states that cleavage leads to an increase in the mass of protoplasm.

**Final Answer**: The incorrect statement is that cleavage leads to an increase in the mass of protoplasm.

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